No abstract

Triglyceride-rich lipoproteins that circulate postprandially are increasingly being recognized as potentially atherogenic. These particles also have been shown to cause endothelial dysfunction. We recently demonstrated that acute parenteral administration of folic acid restores endothelial function in vivo in patients with increased LDL cholesterol levels. In vitro data suggested that this effect could be mediated by a reduction of radical stress. In the present study, therefore, we evaluated the effect of an acute oral fat load on both endothelial function and oxygen radical production. Next, we studied whether 2 weeks of pretreatment with 10 mg folic acid PO could prevent these fat-induced changes. We conducted a prospective, randomized, placebo-controlled study to evaluate the effect of oral folic acid administration (10 mg/d for 2 weeks) on basal endothelial function as well as endothelial function on an acute fat load in 20 healthy volunteers 18 to 33 years old. Endothelial function was assessed as flow-mediated dilatation (FMD). Endothelium-independent dilatation was measured after sublingual nitroglycerin spray. Oxygen radical stress was assessed by measurement of the urinary excretion of the stable radical-damage end product malondialdehyde. During administration of placebo, FMD decreased significantly after an acute oral fat load, with a median from 10.6% (8.3% to 12.2%) to 5.8% (3.0% to 10.2%), P<0.05. During folic acid administration, FMD was unaffected by a fat load, with a median from 9.6% (7.1% to 12.8%) to 9.9% (7.5% to 14.1%), P=NS. The increase in malondialdehyde excretion in the urine after fat loading was also prevented during folic acid administration (absolute increase after an acute fat load during placebo, 0.11+/-0.1 micromol/L versus folic acid, 0.02+/-0.1 micromol/L, P<0.05). The response to the endothelium-independent vasodilator nitroglycerin remained unaltered throughout the study. Pretreatment with oral folic acid prevents the lipid-induced decrease in FMD as well as the lipid-induced increase in urinary radical-damage end products. Because these observations were made in healthy volunteers with normal folate and homocysteine levels, it is suggested that a higher folate intake in the general population may have vasculoprotective effects.

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all common cancers. However, divergent outcomes exist between patients, suggesting distinct underlying tumor biology. Here, we delineated this heterogeneity, compared interconnectivity between classification systems, and experimentally addressed the tumor biology that drives poor outcome. RNA-sequencing of 90 resected specimens and unsupervised classification revealed four subgroups associated with distinct outcomes. The worst-prognosis subtype was characterized by mesenchymal gene signatures. Comparative (network) analysis showed high interconnectivity with previously identified classification schemes and high robustness of the mesenchymal subtype. From species-specific transcript analysis of matching patient-derived xenografts we constructed dedicated classifiers for experimental models. Detailed assessments of tumor growth in subtyped experimental models revealed that a highly invasive growth pattern of mesenchymal subtype tumor cells is responsible for its poor outcome. Concluding, by developing a classification system tailored to experimental models, we have uncovered subtypespecific biology that should be further explored to improve treatment of a group of PDAC patients that currently has little therapeutic benefit from surgical treatment.

The implementation of neoadjuvant chemoradiotherapy (CRT) in esophageal cancer (EC) patients has led to improved survival rates. Worldwide, different CRT regimens are applied. It is unknown how these regimens relate to each other regarding efficacy. Therefore, the aim of this study was to determine the preferred regimen regarding toxicity of, response to CRT, and long-term survival after esophagectomy in EC patients. EC patients in two centers who underwent CRT with different regimens prior to surgery were included in this study. CRT consisted of 50.4Gy combined with two cycles of cisplatin and 5-FU(center A), or 41.4Gy combined with five cycles of carboplatin and paclitaxel (center B). Toxicity, response to therapy and long-term survival were compared between groups. One hundred sisty-five patients were included. Forty-one percent of patients in center A developed ≥1 toxicity ≥ grade 3 versus 25% in center B (P = 0.025). CRT with a cisplatin-based regimen was an independent predictor for development of toxicity ≥ grade 3 (P = 0.043). There were no differences in response between both regimens (P = 0.904). Three-year survival was 61% (A) versus 57% (B) (P = 0.725). The carboplatin/paclitaxel/41.4Gy regimen causes less toxicity compared to the cisplatin/5-FU/50.4Gy regimen with nonsignificant differences in response rates and long-term survival; therefore our results support this regimen to be the preferred regimen for EC patients.